Modern satellite communication systems provide a pervasive and reliable infrastructure to distribute voice, data, and video signals for global exchange and broadcast of information. These satellite communication systems have emerged as a viable option to terrestrial communication systems. Users in a shared access broadband network may be spread over a large geographical area and they may access the shared bandwidth from an access point (e.g., terminal) to an aggregation point, such as a network gateway. An operator on that shared access broadband network may provide, for example, internet services to one or more groups of users that subscribe to bandwidth from the operator. Such a group of terminals may, for example, be an enterprise with terminals in multiple geographical locations, or a virtual network operator (VNO) that provides internet services to users in a large geographic area.
Consider, for example, a digital video broadcast satellite network such as a DVBS-2 based geosynchronous earth orbit satellite network. DVB-S2 is a digital television broadcast standard developed by the DVB project (an industry consortium), and ratified by the European Telecommunications Standards Institute (ETSI) envisioned for broadcasting services, interactive services including Internet access, and data content distribution. Signals transmitted on the forward channel may be based on the DVB-S2 standard, while signals transmitted on the return channel may be based on the Internet Protocol over Satellite (IPoS) standard. In such a network, the IP layer and link gateway may be referred to as the IP gateway (IPGW) and the satellite gateway (SGW), respectively. The data stream may be broadcast to remote network nodes such as Very Small Aperture Terminals (VSATs). In the return direction on a satellite network, multiple VSATs may share one inroute with a certain amount of bandwidth when transmitting data. A bandwidth allocation module can manage and allocate bandwidth on the return channel.
The portion of the electromagnetic spectrum occupied by a particular transmission or communication system (i.e., bandwidth) may be wide or narrow. Wideband signals can be used to transmit large amounts of data in a relatively short period of time. For example, large computer data files and real-time video could benefit from a wideband signal. Narrowband signals can be used to conserve the electromagnetic spectrum when transmitting signals with more modest requirements. For example, base stations and cellular subscriber units in most conventional cellular communication systems transmit and receive voice signals using a relatively narrowband signal.
The amount of usable electromagnetic spectrum is limited by technology, environment, and cost. Extremely high frequency signals require expensive transceiving equipment. Accordingly, communication systems benefit by sharing desirable frequencies. Well known multiple access techniques, such as code division multiple access (CDMA), time division multiple access (TDMA), and frequency division multiple access (FDMA) can be used by a communication system to share the electromagnetic spectrum available to that system. However, these techniques require the signals to be of substantially the same bandwidth. For example, a cellular base station may transmit to a plurality of cellular subscriber units by dividing a portion of the spectrum (e.g., 869 MHz-894 MHz) into a plurality of relatively narrow-band channels (e.g., 30 kHz). Similarly, a satellite communication system may transmit to a plurality of ground stations by dividing a portion of the spectrum (e.g., 3700 MHz-4200 MHz) into a plurality of relatively wideband channels (e.g., 36 MHz). The narrow-band signals and wideband signals occupy distinct portions of the electromagnetic spectrum in order to avoid interfering with each other.